Those who traveled to Naples, or to Genoa and its surrounding Ligurian coast, know that American pizza and focaccia (the Northern Italian version of pizza) are not always the same as what we call Neapolitan, or Napoletana, pizza or Ligurian focaccia. There are a number of reasons for this difference, and it is not necessarily a bad thing that ours are different from theirs. Pizza is, and has always been, a work in progress.
My Greek friends insist that pizza isn't even originally Italian, but Greek, brought to Naples by Peloponnesians escaping the Ottomon Turks or, much earlier, by Trojans fleeing the builders of that famous horse. Indeed, most Greeks are happy to take creidt for contributions from both eras and like to connect nearly everything in Italy to their famous ancestors Odysseus and Aeneas. In relation to pizza, their reasoning may be accurate. Naples, originally called Neapolis was founded in the sixth century B.C. by Greek colonists from the even earlier nearby settlement of Cumae. We also know that the ancient Greeks made a flatbread with toppings called placenta.